U.S. patent number 10,533,146 [Application Number 15/725,415] was granted by the patent office on 2020-01-14 for cleaning formulations for removing residues on semiconductor substrates.
This patent grant is currently assigned to Fujifilm Electronic Materials U.S.A., Inc.. The grantee listed for this patent is Fujifilm Electronic Materials U.S.A., Inc.. Invention is credited to Thomas Dory, Emil A. Kneer, Keeyoung Park, Tomonori Takahashi.
United States Patent |
10,533,146 |
Park , et al. |
January 14, 2020 |
**Please see images for:
( Certificate of Correction ) ** |
Cleaning formulations for removing residues on semiconductor
substrates
Abstract
This disclosure relates to a cleaning composition that contains
1) at least one redox agent; 2) at least one organic solvent
selected from the group consisting of water soluble alcohols, water
soluble ketones, water soluble esters, and water soluble ethers; 3)
at least one metal-containing additive; and 4) water.
Inventors: |
Park; Keeyoung (Gilbert,
AZ), Kneer; Emil A. (Mesa, AZ), Dory; Thomas
(Gilbert, AZ), Takahashi; Tomonori (Shizuoka,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Fujifilm Electronic Materials U.S.A., Inc. |
N. Kingstown |
RI |
US |
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Assignee: |
Fujifilm Electronic Materials
U.S.A., Inc. (N. Kingstown, RI)
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Family
ID: |
61829972 |
Appl.
No.: |
15/725,415 |
Filed: |
October 5, 2017 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20180100128 A1 |
Apr 12, 2018 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62404852 |
Oct 6, 2016 |
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62431620 |
Dec 8, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C11D
3/0042 (20130101); C11D 7/06 (20130101); C11D
7/34 (20130101); C11D 7/50 (20130101); H01L
21/02063 (20130101); C11D 7/5022 (20130101); C11D
7/3245 (20130101); C11D 11/0047 (20130101); C11D
7/20 (20130101); C11D 7/10 (20130101); C11D
7/261 (20130101); C11D 7/263 (20130101); C11D
7/264 (20130101); C11D 7/266 (20130101) |
Current International
Class: |
C11D
7/50 (20060101); C11D 3/00 (20060101); H01L
21/02 (20060101); C11D 7/06 (20060101); C11D
7/10 (20060101); C11D 7/32 (20060101); C11D
7/34 (20060101); C11D 11/00 (20060101); C11D
7/20 (20060101); C11D 7/26 (20060101) |
Field of
Search: |
;510/175 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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WO 2018/067763 |
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Apr 2018 |
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WO |
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Other References
International Search Report and Written Opinion of the
International Searching Authority dated Jan. 5, 2018 (12 pages).
cited by applicant .
The International Preliminary Report on Patentability for
International Application No. PCT/US2017/055231 dated Apr. 18,
2019. cited by applicant .
The International Search Report and Written Opinion of the
International Searching Authority for International Application No.
PCT/US18/22812 by Examiner Lee W. Young dated Jun. 11, 2018 (8
pages). cited by applicant .
The International Preliminary Report on Patentability for
International Application No. PCT/US2018/022812 by Examiner Agnes
Wittmann-Regis dated Oct. 3, 2019. cited by applicant .
The USPTO Non-Final Office Action for U.S. Appl. No. 15/923,116 by
Examiner Gregory E. Webb dated Sep. 30, 2019. cited by
applicant.
|
Primary Examiner: Webb; Gregory E
Attorney, Agent or Firm: Fish & Richardson P.C.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority to U.S. Provisional
Application Ser. No. 62/431,620, filed on Dec. 8, 2016, and U.S.
Provisional Application Ser. No. 62/404,852, filed on Oct. 6, 2016,
both of which are hereby incorporated by reference in their
entirety.
Claims
What is claimed is:
1. A cleaning composition, comprising: 1) at least one redox agent;
2) at least one organic solvent selected from the group consisting
of water soluble alcohols, water soluble ketones, water soluble
esters, and water soluble ethers; 3) at least one metal-containing
additive; and 4) water; wherein the composition is free of a metal
halide of the formula W.sub.zMX.sub.y, in which W is selected from
the group consisting of H, an alkali or alkaline earth metal, and a
metal-ion-free hydroxide base moiety; M is a metal selected from
the group consisting of Si, Ge, Sn, Pt, P, B, Au, Ir, Os, Cr, Ti,
Zr, Rh, Ru and Sb; y is from 4 to 6; and z is 1, 2, or 3.
2. The composition of claim 1, wherein the composition has a pH
from about 7 to about 11.
3. The composition of claim 1, wherein the at least one redox agent
comprises hydroxylamine.
4. The composition of claim 1, wherein the at least one redox agent
is from about 5% to about 20% by weight of the composition.
5. The composition of claim 1, wherein the at least one organic
solvent comprises two organic solvents.
6. The composition of claim 5, wherein the two organic solvents are
each independently selected from the group consisting of alkylene
glycols and alkylene glycol ethers.
7. The composition of claim 1, wherein the at least one organic
solvent is from about 60% to about 95% by weight of the
composition.
8. The composition of claim 1, wherein the at least one
metal-containing additive comprises a metal halide, a metal
hydroxide, a metal boride, a metal alkoxide, a metal oxide, or a
metal-containing ammonium salt.
9. The composition of claim 1, wherein the at least one
metal-containing additive comprises a Group 2A metal, a Group 3B
metal, a Group 4B metal, a Group 5B metal, or a lanthanide
metal.
10. The composition of claim 9, wherein the at least one
metal-containing additive comprises Ca, Ba, Ti, Hf, Sr, La, Ce, W,
V, Nb, or Ta.
11. The composition of claim 1, wherein the at least one
metal-containing additive comprises a tungsten boride,
Ca(OH).sub.2, BaCl.sub.2, SrCl.sub.2, LaCl.sub.3, CeCl.sub.3,
(NH.sub.4).sub.2 TiF.sub.6, BaTiO.sub.3, Ti(OEt).sub.4,
Ti(OCH(CH.sub.3).sub.2).sub.4, HfO.sub.2, V.sub.2O.sub.5,
Nb.sub.2O.sub.5, or TaF.sub.3.
12. The composition of claim 1, wherein the at least one
metal-containing additive is from about 0.001% to about 0.5% by
weight of the composition.
13. The composition of claim 1, wherein the water is from about 5%
to about 28% by weight of the composition.
14. The composition of claim 1, further comprising a pH adjusting
agent.
15. A cleaning composition, comprising: 1) at least one redox
agent; 2) at least one organic solvent selected from the group
consisting of water soluble alcohols, water soluble ketones, water
soluble esters, and water soluble ethers; 3) at least one
metal-containing additive; 4) water; and 5) at least one pH
adjusting agent; wherein the pH adjusting agent is
1,8-diazabicyclo[5.4.0]-7-undecene.
16. The composition of claim 1, further comprising at least one
cleaning additive.
17. The composition of claim 16, wherein the at least one cleaning
additive is a sulfur-containing additive.
18. The composition of claim 17, wherein the sulfur-containing
additive comprises a thiol or a thioether.
19. A cleaning composition, comprising: 1) at least one redox
agent; 2) at least one organic solvent selected from the group
consisting of water soluble alcohols, water soluble ketones, water
soluble esters, and water soluble ethers; 3) at least one
metal-containing additive; 4) water; and 5) at least one
sulfur-containing additive; wherein the sulfur-containing additive
comprises 3-amino-5-mercapto-1H-1,2,4-triazole,
.beta.-mercaptoethanol, 3-amino-5-methylthio-1H-1,2,4-triazole,
1-phenyl-1H-tetrazole-5-thiol, 4 -methyl-4H-1,2,4-triazole-3-thiol,
2-pyridinethiol, or 3-mercapto-propionic acid.
20. The composition of claim 17, wherein the sulfur-containing
additive is from about 0.01% to about 0.15% by weight of the
composition.
21. The composition of claim 16, wherein the at least one cleaning
additive comprises an amino acid.
22. A cleaning composition, comprising: 1) at least one redox
agent; 2) at least one organic solvent selected from the group
consisting of water soluble alcohols, water soluble ketones, water
soluble esters, and water soluble ethers; 3) at least one
metal-containing additive; 4) water; and 5) at least one amino
acid; wherein the amino acid is glycine.
23. The composition of claim 21, wherein the amino acid is from
about 0.01% to about 0.15% by weight of the composition.
24. The composition of claim 1, further comprising at least one
organic acid.
25. The composition of claim 24, wherein the at least one organic
acid comprises a carboxylic acid or a sulfonic acid.
26. The composition of claim 24, wherein the at least one organic
acid is from about 0.1% to about 0.5% by weight of the
composition.
27. The composition of claim 1, further comprising at least one
conductivity enhancing agent selected from the group consisting of
quaternary ammonium hydroxides, quaternary ammonium salts, and
imidazolium salts.
28. The composition of claim 27, wherein the conductivity enhancing
agent is tetramethylammonium hydroxide, tetraethylammonium
hydroxide, tetrabutylammonium hydroxide, tetrabutylammonium
chloride, benzyltrimethylammonium hydroxide, or
1-butyl-3-methyl-imidazolium-methanesulfonate.
29. The composition of claim 27, wherein the at least one
conductivity enhancing agent is from about 1% to about 10% by
weight of the composition.
30. A method, comprising: contacting a semiconductor substrate
containing post etch residues or post ash residues with a cleaning
composition of claim 1.
31. The method of claim 30, wherein the semiconductor substrate
further comprises a layer comprising a material selected from the
group consisting of Cu, Co, W, AlOx, AlN, AlOxNy, Ti, TiN, Ta, TaN,
TiOx, ZrOx, HfOx, and TaOx.
32. The method of claim 30, further comprising rinsing the
semiconductor substrate with a rinse solvent after the contacting
step.
33. The method of claim 32, further comprising drying the
semiconductor substrate after the rinsing step.
34. The method of claim 30, further comprising forming a
semiconductor device from the semiconductor substrate.
35. A cleaning composition, comprising: 1) at least one redox agent
in an amoung of from about 0.5% to about 20% by weight of the
composition; 2) at least one organi solvent selected from the group
consisting of water soluble alcohols, water soluble ketones, water
soluble esters, and water soluble ethers, the at least one organic
solvent being in an amount from about 60% to abou 95% by weight of
the composition; 3) at least one metal-containing additive in an
amount of from about 0.001% to about 0.5% by weight of the
composition; and 4) water in an amount of from about 5% to about
28% by weight of the composition.
36. The composition of claim 35, wherein the composition has a pH
from about 7 to about 11.
37. The composition of claim 35, wherein the at least one redox
agent comprises hydroxylamine.
38. The composition of claim 35, wherein the at least one redox
agent is from about 5% to about 20% by weight of the
composition.
39. The composition of claim 35, wherein the at least one organic
solvent comprises two organic solvents.
40. The composition of claim 39, wherein the two organic solvents
are each independently selected from the group consisting of
alkylene glycols and alkylene glycol ethers.
41. The composition of claim 35, wherein the at least one organic
solvent is from about 60% to about 90% by weight of the
composition.
42. The composition of claim 35, wherein the at least one
metal-containing additive comprises a metal halide, a metal
hydroxide, a metal boride, a metal alkoxide, a metal oxide, or a
metal-containing ammonium salt.
43. The composition of claim 35, wherein the at least one
metal-containing additive comprises a Group 2A metal, a Group 3B
metal, a Group 4B metal, a Group 5B metal, or a lanthanide
metal.
44. The composition of claim 43, wherein the at least one
metal-containing additive comprises Ca, Ba, Ti, Hf, Sr, La, Ce, W,
V, Nb, or Ta.
45. The composition of claim 35, wherein the at least one
metal-containing additive comprises a tungsten boride, Ca(OH)2,
BaClz, SrClz, LaCl3, CeCl3, (NH4)2TiF6, BaTi03, Ti(OEt)4,
Ti(OCH(CH3)2)4, HfOz, V205, szOs, or TaF3.
46. The composition of claim 35, wherein the at least one
metal-containing additive is from about 0.001% to about 0.4% by
weight of the composition.
47. The composition of claim 35, wherein the water is from about 8%
to about 28% of the composition.
48. The composition of claim 35, further comprising a pH adjusting
agent.
49. The composition of claim 48, wherein the pH adjusting agent is
1,8- diazabicyclo[5.4.0]-7-undecene.
50. The composition of claim 35, further comprising at least one
cleaning additive.
51. The composition of claim 50, wherein the at least one cleaning
additive is a sulfur-containing additive.
52. The composition of claim 51, wherein the sulfur-containing
additive comprises a thiol or a thioether.
53. The composition of claim 52, wherein the sulfur-containing
additive comprises 3-amino-5-mercapto-1H-l,2,4-triazole,
.beta.-mercaptoethanol, 3-amino-5-methylthio-1H- 1,2,4-triazole,
1phenyl-1H-tetrazole-5-thiol, 4-methyl-4H-1,2,4-triazole-3-thiol,
2-pyridinethiol, or 3-mercapto-propionic acid.
54. The composition of claim 51, wherein the sulfur-containing
additive is from about 0.01% to about 0.15% by weight of the
composition.
55. The composition of claim 50, wherein the at least one cleaning
additive comprises an amino acid.
56. The composition of claim 55, wherein the amino acid is
glycine.
57. The composition of claim 55, wherein the amino acid is from
about 0.01% to about 0.15% by weight of the composition.
58. The composition of claim 35, further comprising at least one
organic acid.
59. The composition of claim 58, wherein the at least one organic
acid comprises a carboxylic acid or a sulfonic acid.
60. The composition of claim 58, wherein the at least one organic
acid is from about 0.1% to about 0.5% by weight of the
composition.
61. The composition of claim 35, further comprising at least one
conductivity enhancing agent selected from the group consisting of
quaternary ammonium hydroxides, quaternary ammonium salts, and
imidazolium salts.
62. The composition of claim 61, wherein the conductivity enhancing
agent is tetramethylammonium hydroxide, tetraethylammonium
hydroxide, tetrabutylammonium hydroxide, tetrabutylammonium
chloride, benzyltrimethylammonium hydroxide, or 1butyl-3-
methyl-imidazolium-methanesulfonate.
63. The composition of claim 61, wherein the at least one
conductivity enhancing agent is from about 1% to about 10% by
weight of the composition.
64. A method, comprising: contacting a semiconductor substrate
containing post etch residues or post ash residues with a cleaning
composition of claim 35.
Description
BACKGROUND
1. Field of the Disclosure
The present disclosure relates to novel cleaning compositions for
semiconductor substrates and methods of cleaning semiconductor
substrates. More particularly, the present disclosure relates to
cleaning compositions for semiconductor substrates after plasma
etching of metal layers or dielectric material layers deposited on
the substrates and the removal of residues left on the substrates
after bulk resist removal via a plasma ashing process.
2. Discussion of the Background Art
In the manufacture of integrated circuit devices, photoresists are
used as an intermediate mask for transferring the original mask
pattern of a reticle onto the wafer substrate by means of a series
of photolithography and plasma etching steps. One of the essential
steps in the integrated circuit device manufacturing process is the
removal of the patterned photoresist films from the wafer
substrate. In general, this step is carried out by one of two
methods.
One method involves a wet stripping step in which the
photoresist-covered substrate is brought into contact with a
photoresist stripper solution that consists primarily of an organic
solvent and an amine. However, stripper solutions cannot completely
and reliably remove the photoresist films, especially if the
photoresist films have been exposed to UV radiation and plasma
treatments during fabrication. Some photoresist films become highly
crosslinked by such treatments and are more difficult to dissolve
in the stripper solution. In addition, the chemicals used in these
conventional wet-stripping methods are sometimes ineffective for
removing inorganic or organometallic residual materials formed
during the plasma etching of metal or oxide layers with
halogen-containing gases.
An alternative method of removing a photoresist film involves
exposing a photoresist-coated wafer to oxygen-based plasma in order
to burn the resist film from the substrate in a process known as
plasma ashing. However, plasma ashing is also not fully effective
in removing the plasma etching by-products noted above. Instead,
removal of these plasma etch by-products is typically accomplished
by subsequently exposing the processed metal and dielectric thin
films to certain cleaning solutions.
Metal substrates are generally susceptible to corrosion. For
example, substrates such as aluminum, copper, aluminum-copper
alloy, tungsten nitride, tungsten (W), cobalt (Co), titanium oxide,
other metals and metal nitrides, will readily corrode and
dielectrics [ILD, ULK] can be etched by using conventional cleaning
chemistries. In addition, the amount of corrosion tolerated by the
integrated circuit device manufacturers is getting smaller and
smaller as the device geometries shrink.
At the same time, as residues become harder to remove and corrosion
must be controlled to ever lower levels, cleaning solutions should
be safe to use and environmentally friendly.
Therefore, the cleaning solution should be effective for removing
the plasma etch and plasma ash residues and should also be
non-corrosive to all exposed substrate materials.
SUMMARY OF THE DISCLOSURE
The present disclosure is directed to non-corrosive cleaning
compositions that are useful for removing residues (e.g., plasma
etch and/or plasma ashing residues) from a semiconductor substrate
as an intermediate step in a multistep manufacturing process. These
residues include a range of relatively insoluble mixtures of
organic compounds such as residual photoresist; organometallic
compounds; metal oxides such as aluminum oxides (AlOx), titanium
oxides (TiOx), zirconium oxides (ZrOx), tantalum oxides (TaOx), and
hafnium oxides (HfOx) (which are formed as reaction by-products
from exposed metals); metals such as aluminum (Al), aluminum/copper
alloy, copper (Cu), titanium (Ti), tantalum (Ta), tungsten (W), and
cobalt (Co); metal nitrides such as aluminum nitrides (AlN),
aluminum oxide nitrides (AlOxNy), titanium nitrides (TiN), tantalum
nitrides (TaN), and tungsten nitrides (WN); their alloys; and other
materials. An advantage of the cleaning composition described
herein is that it can clean a broad range of residues encountered
and be generally non-corrosive to exposed substrate materials
(e.g., exposed metals (such as aluminum, aluminum/copper alloy,
copper, titanium, tantalum, tungsten, and cobalt), metal nitrides
(such as titanium, tantalum, and tungsten nitrides), and their
alloys).
In one aspect, the present disclosure features a cleaning
composition containing
1) at least one redox agent;
2) at least one organic solvent selected from the group consisting
of water soluble alcohols, water soluble ketones, water soluble
esters, and water soluble ethers;
3) at least one metal-containing additive; and
4) water.
The present disclosure also features a method of cleaning residues
from a semiconductor substrate. The method includes contacting a
semiconductor substrate containing post etch residues and/or post
ash residues with a cleaning composition described herein. For
example, the method can include the steps of: (A) providing a
semiconductor substrate containing post etch and/or post ash
residues; (B) contacting said semiconductor substrate with a
cleaning composition described herein; (C) rinsing said
semiconductor substrate with a suitable rinse solvent; and (D)
optionally, drying said semiconductor substrate by any means that
removes the rinse solvent and does not compromise the integrity of
said semiconductor substrate.
DETAILED DESCRIPTION OF THE DISCLOSURE
As defined herein, unless otherwise noted, all percentages
expressed should be understood to be percentages by weight to the
total weight of the cleaning composition. Unless otherwise noted,
ambient temperature is defined to be between about 16 and about 27
degrees Celsius (.degree. C.), such as 25.degree. C.
The terms "layer" and "film" are used interchangeably.
As defined herein, a "water-soluble" substance (e.g., a
water-soluble alcohol, ketone, ester, or ether) refers to a
substance having a solubility of at least 5% by weight in water at
25.degree. C.
One embodiment of the present disclosure is directed to a
non-corrosive cleaning composition including:
1) at least one redox agent;
2) at least one organic solvent selected from the group consisting
of water soluble alcohols, water soluble ketones, water soluble
esters, and water soluble ethers;
3) at least one metal-containing additive; and
4) water.
The compositions of this disclosure contain at least one redox
agent, which is believed to aid in the dissolution of residues on
the semiconductor surface such as photoresist residues, metal
residues, and metal oxide residues. As used herein, the term "redox
agent" refers to a compound that can induce an oxidation and/or a
reduction in a semiconductor cleaning process. An example of a
suitable redox agent is hydroxylamine. In some embodiments, the
redox agent or the cleaning composition described herein does not
include a peroxide (e.g., hydrogen peroxide).
In some embodiments, the compositions of this disclosure include at
least about 0.5% by weight (e.g., at least about 1% by weight, at
least about 2% by weight, at least about 3% by weight, or at least
about 5% by weight) and/or at most about 20% by weight (e.g., at
most about 17% by weight, at most about 15% by weight, at most
about 12% by weight, or at most about 10% by weight) the redox
agent.
The compositions of this disclosure contain at least one (e.g.,
two, three, four, or more) organic solvent selected from the group
of water soluble alcohols, water soluble ketones, water soluble
esters, and water soluble ethers (e.g., glycol diethers).
Classes of water soluble alcohols include, but are not limited to,
alkane diols (including, but not limited to, alkylene glycols),
glycols, alkoxyalcohols (including, but not limited to, glycol
monoethers), saturated aliphatic monohydric alcohols, unsaturated
non-aromatic monohydric alcohols, and low molecular weight alcohols
containing a ring structure.
Examples of water soluble alkane diols includes, but are not
limited to, 2-methyl-1,3-propanediol, 1,3-propanediol,
2,2-dimethyl-1,3-propanediol, 1,4-butanediol, 1,3-butanediol,
1,2-butanediol, 2,3-butanediol, pinacol, and alkylene glycols.
Examples of water soluble alkylene glycols include, but are not
limited to, ethylene glycol, propylene glycol, hexylene glycol,
diethylene glycol, dipropylene glycol, triethylene glycol and
tetraethyleneglycol.
Examples of water soluble alkoxyalcohols include, but are not
limited to, 3-methoxy-3-methyl-1-butanol, 3-methoxy-1-butanol,
1-methoxy-2-butanol, and water soluble glycol monoethers.
Examples of water soluble glycol monoethers include, but are not
limited to, ethylene glycol monomethyl ether, ethylene glycol
monoethyl ether, ethylene glycol mono n-propyl ether, ethylene
glycol monoisopropyl ether, ethylene glycol mono n-butyl ether,
diethylene glycol monomethyl ether, diethylene glycol monoethyl
ether, diethylene glycol monobutylether, triethylene glycol
monomethyl ether, triethylene glycol monoethyl ether, triethylene
glycol monobutyl ether, 1-methoxy-2-propanol, 2-methoxy-1-propanol,
1-ethoxy-2-propanol, 2-ethoxy-1-propanol, propylene glycol
mono-n-propyl ether, dipropylene glycol monomethyl ether,
dipropylene glycol monoethyl ether, dipropylene glycol
mono-n-propyl ether, tripropylene glycol monoethyl ether,
tripropylene glycol monomethyl ether and ethylene glycol monobenzyl
ether, and diethylene glycol monobenzyl ether.
Examples of water soluble saturated aliphatic monohydric alcohols
include, but are not limited to, methanol, ethanol, n-propyl
alcohol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol,
tert-butyl alcohol, 2-pentanol, t-pentyl alcohol, and 1
-hexanol.
Examples of water soluble unsaturated non-aromatic monohydric
alcohols include, but are not limited to, allyl alcohol, propargyl
alcohol, 2-butenyl alcohol, 3-butenyl alcohol, and
4-penten-2-ol.
Examples of water soluble, low molecular weight alcohols containing
a ring structure include, but are not limited to,
tetrahydrofurfuryl alcohol, furfuryl alcohol, and
1,3-cyclopentanediol.
Examples of water soluble ketones include, but are not limited to,
acetone, propanone, cyclobutanone, cyclopentanone, cyclohexanone,
diacetone alcohol, 2-butanone, 2,5-hexanedione,
1,4-cyclohexanedione, 3-hydroxyacetophenone, 1,3-cyclohexanedione,
and cyclohexanone.
Examples of water soluble esters include, but are not limited to,
ethyl acetate, glycol monoesters such as ethylene glycol
monoacetate, diethyleneglycol monoacetate, and glycol monoether
monoesters such as propylene glycol monomethyl ether acetate,
ethylene glycol monomethyl ether acetate, propylene glycol
monoethyl ether acetate, and ethylene glycol monoethylether
acetate.
In some embodiments, the cleaning compositions of this disclosure
include at least about 60% by weight (e.g., at least about 65% by
weight, at least about 70% by weight, or at least about 75% by
weight) and/or at most about 95% by weight (e.g., at most about 90%
by weight, at most about 85% by weight, or at most about 80% by
weight) the at least one organic solvent.
The cleaning compositions of the present disclosure further include
water. Preferably, the water is de-ionized and ultra-pure, contains
no organic contaminants and has a minimum resistivity of about 4 to
about 17 mega Ohms. More preferably, the resistivity of the water
is at least 17 mega Ohms.
In some embodiments, the compositions of this disclosure include at
least about 5% by weight (e.g., at least about 8% by weight, at
least about 12% by weight, or at least about 16% by weight) and/or
at most about 28% by weight (e.g., at most about 24% by weight, at
most about 20% by weight, or at most about 18% by weight)
water.
Metal-containing additives contemplated for use in the cleaning
compositions of the disclosure include metals selected from Group
2A metals, Group 3B metals, Group 4B metals, Group 5B metals, and
lanthanide metals. In some embodiments, the metal is Ca, Ba, Ti,
Hf, Sr, La, Ce, W, V, Nb, or Ta. In some embodiments, the metal is
selected from Group 4B metals (such as Ti or Hf).
The metal-containing additive can be in the form of a metal halide,
a metal hydroxide, a metal boride, a metal alkoxide, a metal oxide,
or a metal-containing ammonium salt. In some embodiments, the
metal-containing additive is an ammonium salt. The ammonium salt
can be a salt of formula (I): (NH.sub.4).sub.mMX.sub.n (I); in
which m is 1, 2, 3, or 4; n is 1, 2, 3, 4, 5, or 6; M is a metal
ion (such as an ion of a Group 2A metal, Group 3B metal, Group 4B
metal, Group 5B metal, or lanthanide metal); and X is a halide ion
(e.g., F, Cl, Br, or I). In certain embodiments, the
metal-containing additive is ammonium hexafluorotitanate. Examples
of metal-containing additives can include tungsten borides,
Ca(OH).sub.2, BaCl.sub.2, SrCl.sub.2, LaCl.sub.3, CeCl.sub.3,
(NH.sub.4).sub.2TiF.sub.6, BaTiO.sub.3, Ti(OEt).sub.4,
Ti(OCH(CH.sub.3).sub.2).sub.4, HfO.sub.2, V.sub.2O.sub.5,
Nb.sub.2O.sub.5, or TaF.sub.3.
In some embodiments, the metal-containing additive can be in an
amount of at least about 0.001% by weight (e.g., at least about
0.002% by weight, at least about 0.004% by weight, at least about
0.006% by weight, at least about 0.008% by weight, or at least
about 0.01% by weight) and/or at most about 0.5% by weight (e.g.,
at most about 0.4% by weight, at most about 0.3% by weight, at most
about 0.2% by weight, at most about 0.1% by weight, at most about
0.08% by weight, at most about 0.06% by weight, at most about 0.04%
by weight, at most about 0.02% by weight, or at most about 0.01% by
weight) of the composition. Without wishing to be bound by theory,
it is believed that including the metal-containing additive in the
amount specified above in a cleaning composition can reduce the
corrosion effects of the composition, i.e., lowering the etch rate
of the cleaning composition towards the exposed substrate materials
(e.g., exposed metals or dielectric materials) that are not
intended to be removed during the cleaning process.
The cleaning compositions of this disclosure can optionally contain
at least one cleaning additive to improve their cleaning capability
(e.g., removing etch or ash residues) and/or reduce their corrosion
effects. In some embodiments, the cleaning additive can be a
sulfur-containing additive or an amino acid. In some embodiments,
the cleaning compositions can include both a sulfur-containing
additive and an amino acid.
Sulfur-containing additives contemplated for use in the cleaning
compositions of the disclosure are not particularly limited. In
some embodiments, the sulfur-containing additive is a molecule
bearing a thiol moiety (i.e., SH) or thioether moiety (e.g., SR in
which R is C.sub.1-C.sub.10 alkyl). In some embodiments, the
sulfur-containing additive can be an alcohol, an acid, an amine, or
a heterocyclic compound that contains a thiol or thioether moiety.
Examples of sulfur-containing additives include, but are not
limited to, 3-amino-5-mercapto-1H-1,2,4-triazole;
.beta.-mercaptoethanol; 3-amino-5-methylthio-1H-1,2,4-triazole;
1-phenyl-1H-tetrazole-5-thiol; 4-methyl-4H-1,2,4-triazole-3-thiol;
2-pyridinethiol; 3-mercapto-propionic acid, and the like. In some
embodiments, the sulfur-containing additive may exclude
sulfur-containing organic acids.
In some embodiments, the sulfur-containing additive can be in an
amount of at least about 0.01% by weight (e.g., at least about
0.02% by weight, at least about 0.04% by weight, at least about
0.05% by weight, at least about 0.06% by weight, or at least about
0.08% by weight) and/or at most about 0.15% by weight (e.g., at
most about 0.14% by weight, at most about 0.12% by weight, at most
about 0.1% by weight, at most about 0.08% by weight, or at most
about 0.07% by weight) of the composition. Without wishing to be
bound by theory, it is believed that including the
sulfur-containing additive in the amount specified above in a
cleaning composition can improve the cleaning capability of the
composition for removing post etch and/or post ash residues and/or
lower the etch rate of the cleaning composition towards the exposed
substrate materials (e.g., exposed metals or dielectric materials)
that are not intended to be removed during the cleaning
process.
In some embodiments, the cleaning additive can include at least one
amino acids. Examples of suitable amino acids include glycine. The
amino acid can be a naturally occurring amino acid or a
non-naturally occurring amino acid (e.g., a synthetic amino acid).
The amino acid can be a D- or L-amino acid.
In some embodiments, the amino acid can be in an amount of at least
about 0.01% by weight (e.g., at least about 0.02% by weight, at
least about 0.04% by weight, at least about 0.05% by weight, at
least about 0.06% by weight, or at least about 0.08% by weight)
and/or at most about 0.15% by weight (e.g., at most about 0.14% by
weight, at most about 0.12% by weight, at most about 0.1% by
weight, at most about 0.08% by weight, or at most about 0.07% by
weight) of the composition. Without wishing to be bound by theory,
it is believed that including the amino acid in the amount
specified above in a cleaning composition can improve the cleaning
capability of the composition for removing post etch and/or post
ash residues and/or lower the etch rate of the cleaning composition
towards the exposed substrate materials (e.g., exposed metals or
dielectric materials) that are not intended to be removed during
the cleaning process.
In some embodiments, the cleaning compositions of this disclosure
can contain one or more organic acids. The organic acids can be
used in the cleaning compositions in the presence or absence of the
cleaning additive mentioned above (e.g., the sulfur-containing
additive or the amino acid). Organic acids contemplated for use in
the cleaning compositions of the disclosure include carboxylic
acids and sulfonic acids. Exemplary carboxylic acid contemplated
for use in the compositions of the disclosure include, but are not
limited to, monocarboxylic acids, bicarboxylic acids, tricarboxylic
acids, .alpha.-hydroxyacids and .beta.-hydroxyacids of
monocarboxylic acids, .alpha.-hydroxyacids or .beta.-hydroxyacids
of bicarboxylic acids, or .alpha.-hydroxyacids and
.beta.-hydroxyacids of tricarboxylic acids. In some embodiments,
the at least one carboxylic acid includes citric acid, maleic acid,
fumaric acid, lactic acid, glycolic acid, oxalic acid, tartaric
acid, succinic acid, or benzoic acid. Examples of sulfonic acids of
include, but are not limited to, methanesulfonic acid,
trifluoromethanesulfonic acid, ethanesulfonic acid,
trifluoroethanesulfonic acid, perfluoroethylsulfonic acid,
perfluoro(ethoxyethane)sulfonic acid,
perfluoro(methoxyethane)sulfonic acid, dodecylsulfonic acid,
perfluorododecylsulfonic acid, butanesulfonic acid,
perfluorobutanesulfonic acid, propanesulfonic acid,
perfluoropropanesulfonic acid, octylsulfonic acid,
pefluorooctanesulfonic acid, methanedisulfonic acid,
2-methylpropanesulfonic acid, cyclohexylsulfonic acid,
camphorsulfonic acids, perfluorohexanesulfonic acid,
ethanedisulfonic acid, benzylsulfonic acid,
hydroxyphenylmethanesulfonic acid, naphthylmethanesulfonic acid,
and norbornanesulfonic acids, benzenesulfonic acid,
chlorobenzenesulfonic acids, bromobenzenesulfonic acids,
fluorobenzenesulfonic acids, hydroxybenzenesulfonic acids,
nitrobenzenesulfonic acids, 2-hydroxy-5-sulfobenzoic acid,
benzenedisulfonic acids, toluenesulfonic acids (e.g.,
p-toluenesulfonic acid), methylchlorobenzenesulfonic acids,
dodecylbenzenesulfonic acids, butylbenzenesulfonic acids,
cyclohexylbenzenesulfonic acids, picrylsulfonic acid,
dichlorobenzenesulfonic acids, dibromobenzenesulfonic acids, and
2,4,5-trichlorobenzenesulfonic acid.
In some embodiments, the organic acid can be in an amount of at
least about 0.1% by weight (e.g., at least about 0.12% by weight,
at least about 0.14% by weight, at least about 0.16% by weight, at
least about 0.18% by weight, or at least about 0.2% by weight)
and/or at most about 0.5% by weight (e.g., at most about 0.4% by
weight, at most about 0.3% by weight, at most about 0.2% by weight,
at most about 0.18% by weight, or at most about 0.16% by weight) of
the composition. Without wishing to be bound by theory, it is
believed that the organic acid can serve as a chelating agent in
the cleaning composition to facilitate the removal of post etch
and/or post ash residues.
The cleaning compositions of this disclosure can optionally contain
at least one conductivity enhancing agent. Suitable conductivity
enhancing agents include quaternary ammonium hydroxides, quaternary
ammonium salts, and imidazolium salts. For example, a suitable
conductivity enhancing agent can be tetramethylammonium hydroxide,
tetraethylammonium hydroxide, tetrabutylammonium hydroxide,
tetrabutylammonium chloride, benzyltrimethylammonium hydroxide, or
1-butyl-3-methyl-imidazolium-methanesulfonate.
In some embodiments, the conductivity enhancing agent can be from
at least about 1% (e.g., at least about 2% by weight, at least
about 3% by weight, at least about 4% by weight, at least about 5%
by weight, or at least about 6% by weight) to at most about 10% by
weight (e.g., at most about 9% by weight, at most about 8% by
weight, at most about 7% by weight, at most about 6% by weight, or
at most about 5% by weight) of the composition. Without wishing to
be bound by theory, it is believed that the conductivity enhancing
agent can reduce Co loss or corrosion during the cleaning process
and can serve as a Co corrosion inhibitor.
The cleaning compositions of this disclosure can optionally contain
at least one pH adjusting agent (e.g., an acid or a base) to
control the pH to from about 7 to about 11. In some embodiments,
the compositions of this disclosure can have a pH of at least about
7 (e.g., at least about 7.5, at least about 8, or at least about
8.5) to at most about 11 (e.g., at most about 10.5, at most about
10, at most about 9.5, at most about 9). Without wishing to be
bound by theory, it is believed that a cleaning composition having
a pH higher than 11 decreases the plasma etch residue cleaning to
an impractical level for complete cleaning and that a pH lower than
7 would increase the etch rate of certain metals or dielectric
materials to an undesirable level. The effective pH can vary
depending on the types and amounts of the ingredients used in the
compositions described herein.
The amount of the pH adjusting agent required, if any, can vary as
the concentrations of the other components are varied in different
formulations, particularly the hydroxylamine and the organic acid,
and as a function of the molecular weight of the particular pH
adjusting agent employed. In general, the pH adjusting agent
concentration ranges from about 0.1% to about 3% by weight of the
cleaning composition. In some embodiments, the cleaning
compositions of this disclosure include at least about 0.1% by
weight (e.g., at least about 0.5% by weight, at least about 1% by
weight, or at least about 1.5% by weight) and/or at most about 3%
by weight (e.g., at most about 2.5% by weight, at most about 2% by
weight, or at most about 1.5% by weight) the pH adjusting
agent.
In general, the pH adjusting agent is free of any metal ion (except
for a trace amount of metal ion impurities). Suitable metal ion
free pH adjusting agents include ammonium hydroxide, quaternary
ammonium hydroxides, monoamines (including alkanolamines), imines
(such as 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) and
1,5-diazabicyclo[4.3.0]-5-nonene), and guanidine salts (such as
guanidine carbonate).
Examples of suitable quaternary ammonium hydroxides include, but
are not limited to, tetramethyl ammonium hydroxide, tetraethyl
ammonium hydroxide, tetrapropyl ammonium hydroxide, tetrabutyl
ammonium hydroxide, dimethyldiethylammonium hydroxide, choline,
tetraethanolammonium hydroxide, benzyltrimethylammonium hydroxide,
benzyltriethylammonium hydroxide, and benzyltributylammonium
hydroxide.
Examples of suitable monoamines include, but are not limited to,
triethylamine, tributylamine, tripentylamine, ethanolamine,
diethanolamine, diethylamine, butylamine, dibutylamine, and
benzylamine.
In addition, in some embodiments, the cleaning compositions of the
present disclosure may contain additives such as, additional pH
adjusting agents, corrosion inhibitors (e.g., a substituted or
unsubstituted benzotriazole), surfactants, additional organic
solvents, biocides, and defoaming agents as optional
components.
Examples of suitable defoaming agents include polysiloxane
defoamers (e.g., polydimethylsiloxane), polyethylene glycol methyl
ether polymers, ethylene oxide/propylene oxide copolymers, and
glycidyl ether capped acetylenic diol ethoxylates (such as those
described in U.S. Pat. No. 6,717,019, herein incorporated by
reference).
In some embodiments, the cleaning compositions of the present
disclosure may specifically exclude one or more of the additive
components, in any combination, if more than one. Such components
are selected from the group consisting of oxygen scavengers,
quaternary ammonium hydroxides, amines, alkali metal and alkaline
earth bases (such as NaOH, KOH, LiOH, magnesium hydroxide, and
calcium hydroxide), surfactants other than a defoamer, fluoride
containing compounds, oxidizing agents (e.g., peroxides, hydrogen
peroxide, ferric nitrate, potassium iodate, potassium permanganate,
nitric acid, ammonium chlorite, ammonium chlorate, ammonium iodate,
ammonium perborate, ammonium perchlorate, ammonium periodate,
ammonium persulfate, tetramethylammonium chlorite,
tetramethylammonium chlorate, tetramethylammonium iodate,
tetramethylammonium perborate, tetramethylammonium perchlorate,
tetramethylammonium periodate, tetramethylammonium persulfate, urea
hydrogen peroxide, and peracetic acid), abrasives, silicates,
hydroxycarboxylic acids, carboxylic and polycarboxylic acids
lacking amino groups, non-azole corrosion inhibitors, guanidine,
guanidine salts, inorganic acids (e.g., sulfonic acids, sulfuric
acid, sulfurous acid, nitrous acid, nitric acid, phosphorus acid,
and phosphoric acid), pyrrolidone, polyvinyl pyrrolidone, metal
halides, metal halides of the formula W.sub.zMX.sub.y, wherein W is
selected from H, an alkali or alkaline earth metal, and a
metal-ion-free hydroxide base moiety; M is a metal selected from
the group consisting of Si, Ge, Sn, Pt, P, B, Au, Ir, Os, Cr, Ti,
Zr, Rh, Ru and Sb; y is from 4 to 6; and z is 1, 2, or 3, and
corrosion inhibitors other than those described in this
disclosure.
In some embodiments, the cleaning compositions of the present
disclosure are not specifically designed to remove bulk photoresist
films from semiconductor substrates. Rather, the cleaning
compositions of the present disclosure can be designed to remove
all residues after bulk resist removal by dry or wet stripping
methods. Therefore, in some embodiments, the cleaning method of the
present disclosure is preferably employed after a dry or wet
photoresist stripping process. This photoresist stripping process
is generally preceded by a pattern transfer process, such as an
etch or implant process, or it is done to correct mask errors
before pattern transfer. The chemical makeup of the residue will
depend on the process or processes preceding the cleaning step.
Any suitable dry stripping process can be used to remove bulk
resist from semiconductor substrates. Examples of suitable dry
stripping processes include oxygen based plasma ashing, such as a
fluorine/oxygen plasma or a N.sub.2/H.sub.2 plasma; ozone gas
phase-treatment; fluorine plasma treatment, hot H.sub.2 gas
treatment (such as that described in U.S. Pat. No. 5,691,117
incorporated herein by reference in its entirety), and the like. In
addition, any conventional organic wet stripping solution known to
a person skilled in the art can be used to remove bulk resist from
semiconductor substrates.
A preferred stripping process used in combination with the cleaning
method of the present disclosure is a dry stripping process.
Preferably, this dry stripping process is the oxygen based plasma
ashing process. This process removes most of the photoresist from
the semiconductor substrate by applying a reactive-oxygen
atmosphere at elevated temperatures (typically 250.degree. C.) at
vacuum conditions (i.e., 1 torr). Organic materials are oxidized by
this process and are removed with the process gas. However, this
process does not remove inorganic or organometallic contamination
from the semiconductor substrate. A subsequent cleaning of the
semiconductor substrate with the cleaning composition of the
present disclosure is typically necessary to remove those
residues.
In some embodiments, there are provided methods of cleaning
residues from a semiconductor substrate. Such methods can be
performed, for example, by contacting a semiconductor substrate
containing post etch residues and/or post ash residues with a
cleaning composition described herein. The method can further
include rinsing the semiconductor substrate with a rinse solvent
after the contacting step and/or drying the semiconductor substrate
after the rinsing step. In some embodiments, the semiconductor
substrate can further include a material (e.g., an exposed
material) or a layer of the material, where the material is
selected from the group consisting of Cu, Co, W, AlOx, AlN, AlOxNy,
Ti, TiN, Ta, TaN, TiOx, ZrOx, HfOx, and TaOx.
In some embodiments, the cleaning method includes the steps of: (A)
providing a semiconductor substrate containing post etch and/or
post ash residues; (B) contacting said semiconductor substrate with
a cleaning composition described herein; (C) rinsing said
semiconductor substrate with a suitable rinse solvent; and (D)
optionally, drying said semiconductor substrate by any means that
removes the rinse solvent and does not compromise the integrity of
said semiconductor substrate. In some embodiments, the cleaning
method further includes forming a semiconductor device (e.g., an
integrated circuit device such as a semiconductor chip) from the
semiconductor substrate obtained by the method described above.
The semiconductor substrates to be cleaned in this method can
contain organic and organometallic residues, and additionally, a
range of metal oxides that need to be removed. Semiconductor
substrates typically are constructed of silicon, silicon germanium,
Group III-V compounds like GaAs, or any combination thereof. The
semiconductor substrates can additionally contain exposed
integrated circuit structures such as interconnect features (e.g.,
metal lines and dielectric materials). Metals and metal alloys used
for interconnect features include, but are not limited to,
aluminum, aluminum alloyed with copper, copper, titanium, tantalum,
cobalt, and silicon, titanium nitride, tantalum nitride, tungsten,
and their alloys. Said semiconductor substrate can also contain
layers of interlayer dielectrics, silicon oxide, silicon nitride,
silicon carbide, titanium oxide, and carbon doped silicon
oxides.
The semiconductor substrate can be contacted with a cleaning
composition by any suitable method, such as placing the cleaning
composition into a tank and immersing and/or submerging the
semiconductor substrates into the cleaning composition, spraying
the cleaning composition onto the semiconductor substrate,
streaming the cleaning composition onto the semiconductor
substrate, or any combinations thereof. Preferably, the
semiconductor substrates are immersed into the cleaning
composition.
The cleaning compositions of the present disclosure may be
effectively used up to a temperature of about 90.degree. C. (e.g.,
from about 25.degree. C. to about 80.degree. C., from about
30.degree. C. to about 60.degree. C., or from about 40.degree. C.
to about 60.degree. C.).
Similarly, cleaning times can vary over a wide range depending on
the particular cleaning method and temperature employed. When
cleaning in an immersion batch type process, a suitable time range
is, for example, up to about 60 minutes (e.g., from about 1 minute
to about 60 minutes, from about 3 minutes to about 20 minutes, or
from about 4 minutes to about 15 minutes).
Cleaning times for a single wafer process may range from about 10
seconds to about 5 minutes (e.g., from about 15 seconds to about 4
minutes, from about 15 seconds to about 3 minutes, or from about 20
seconds to about 2 minutes).
To further promote the cleaning ability of the cleaning composition
of the present disclosure, mechanical agitation means may be
employed. Examples of suitable agitation means include circulation
of the cleaning composition over the substrate, streaming or
spraying the cleaning composition over the substrate, and
ultrasonic or megasonic agitation during the cleaning process. The
orientation of the semiconductor substrate relative to the ground
may be at any angle. Horizontal or vertical orientations are
preferred.
The cleaning compositions of the present disclosure can be used in
conventional cleaning tools known to those skilled in the art. A
significant advantage of the compositions of the present disclosure
is that they include relatively non-toxic, non-corrosive, and
non-reactive components in whole and in part, whereby the
compositions are stable in a wide range of temperatures and process
times. The compositions of the present disclosure are chemically
compatible with practically all materials used to construct
existing and proposed semiconductor wafer cleaning process tools
for batch and single wafer cleaning.
Subsequent to the cleaning, the semiconductor substrate can be
rinsed with a suitable rinse solvent for about 5 seconds up to
about 5 minutes with or without agitation means. Examples of
suitable rinse solvents include, but are not limited to, deionized
(DI) water, methanol, ethanol, isopropyl alcohol,
N-methylpyrrolidinone, gamma-butyrolactone, dimethyl sulfoxide,
ethyl lactate and propylene glycol monomethyl ether acetate.
Alternatively, aqueous rinses with pH>8 (such as dilute aqueous
ammonium hydroxide) may be employed. Preferred examples of rinse
solvents include, but are not limited to, dilute aqueous ammonium
hydroxide, DI water, methanol, ethanol and isopropyl alcohol. More
preferred rinse solvents are dilute aqueous ammonium hydroxide, DI
water and isopropyl alcohol. The most preferred rinse solvents are
dilute aqueous ammonium hydroxide and DI water. The solvent may be
applied using means similar to that used in applying a cleaning
composition described herein. The cleaning composition may have
been removed from the semiconductor substrate prior to the start of
the rinsing step or it may still be in contact with the
semiconductor substrate at the start of the rinsing step.
Preferably, the temperature employed in the rinsing step is between
16.degree. C. and 27.degree. C.
Optionally, the semiconductor substrate is dried after the rinsing
step. Any suitable drying means known in the art may be employed.
Examples of suitable drying means include spin drying, flowing a
dry gas across the semiconductor substrate, or heating the
semiconductor substrate with a heating means such as a hotplate or
infrared lamp, Marangoni drying, Rotagoni drying, IPA drying or any
combinations thereof. Drying times will be dependent on the
specific method employed but are typically on the order of 30
seconds up to several minutes.
In some embodiments, a method of manufacturing an integrated device
using a cleaning composition described herein can include the
following steps. First, a layer of a photoresist is applied to a
semiconductor substrate. The semiconductor substrate thus obtained
can then undergo a pattern transfer process, such as an etch or
implant process, to form an integrated circuit. The bulk of the
photoresist can then be removed by a dry or wet stripping method
(e.g., an oxygen based plasma ashing process). Remaining residues
on the semiconductor substrate can then be removed using a cleaning
composition described herein in the manner described above. The
semiconductor substrate can subsequently be processed to form one
or more additional circuits on the substrate or can be processed to
form into a semiconductor chip by, for example, assembling (e.g.,
dicing and bonding) and packaging (e.g., chip sealing).
The contents of all publications cited herein (e.g., patents,
patent application publications, and articles) are hereby
incorporated by reference in their entirety.
EXAMPLES
The present disclosure is illustrated in more detail with reference
to the following examples, which are for illustrative purposes and
should not be construed as limiting the scope of the present
disclosure. Any percentages listed are by weight (wt %) unless
otherwise specified. Controlled stirring during testing was done
with a 1 inch stirring bar at 300 rpm unless otherwise noted.
General Procedure 1
Formulation Blending
Compositions of the disclosure were prepared by mixing, while
stirring, the organic solvents, and ultra-pure deionized water
(DIW). After a uniform solution was achieved, the remaining
components were added. All components used were commercially
available and of high purity.
General Procedure 2
Cleaning Evaluation with Beaker Test
The cleaning of PER (Post Etch Residue) from a substrate was
carried out with the above-described cleaning compositions using a
multilayered substrate of Photoresist/TiOx/SiN/Co/ILD (ILD=Inter
Layer Dielectric) or photoresist/TiOx/SiN/W/ILD that had been
patterned lithographically, etched in a plasma metal etcher, and
followed by oxygen plasma ashing to remove the top layer of
photoresist completely.
The test coupons were held using 4'' long plastic locking tweezers,
whereby the coupon could then be suspended into a 500 ml volume
glass beaker containing approximately 200 milliliters of the
cleaning compositions of the present disclosure. Prior to immersion
of the coupon into the cleaning composition, the composition was
pre-heated to the desired test condition temperature (typically
40.degree. C. or 60.degree. C. as noted) with controlled stirring.
The cleaning tests were then carried out by placing the coupon
which was held by the plastic tweezers into the heated composition
in such a way that the PER layer containing side of the coupon
faced the stir bar. The coupon was left static in the cleaning
composition for a time period (typically 2 to 5 minutes) while the
composition was kept at the test temperature under controlled
stirring. When the desired cleaning time was completed, the coupon
was quickly removed from the cleaning composition and placed in a
500 ml plastic beaker filled with approximately 400 ml of DI water
at ambient temperature (.about.17.degree. C.) with gentle stirring.
The coupon was left in the beaker of DI water for approximately 30
seconds, and then quickly removed, and rinsed under a DI water
stream at ambient temperature for about 30 seconds. The coupon was
immediately exposed to a nitrogen gas stream from a hand held
nitrogen blowing gun, which caused any droplets on the coupon
surface to be blown off the coupon, and further, to completely dry
the coupon device surface. Following this final nitrogen drying
step, the coupon was removed from the plastic tweezers holder and
placed into a covered plastic carrier with the device side up for
short term storage no greater than about 2 hours. The scanning
electron microscopy (SEM) images were then collected for key
features on the cleaned test coupon device surface.
General Procedure 3
Materials Compatibility Evaluation with Beaker Test
The blanket Co on silicon substrate, W on silicon substrate, TiOx
on SiO.sub.2 on silicon substrate, SiN on silicon substrate, ILD on
silicon substrate, SiC on silicon substrate, and W alloy on silicon
substrate were diced into approximately 1 inch.times.1 inch square
test coupons for the materials compatibility tests. The test
coupons were initially measured for thickness or sheet resistance
by the 4-point probe, CDE Resmap 273 for metallic film (Co, W), or
by Elipsometry for dielectric film (TiOx, SiN and ILD) using a
Woollam M-2000X. The test coupons were then installed on the 4''
long plastic locking tweezers and treated as described in the
cleaning procedure in General Procedure 2 with the Co, W, W alloy,
TiOx, SiN, SiC, or ILD layer containing side of the coupon faced
the stir bar for 10 minutes.
After the final nitrogen drying step, the coupon was removed from
the plastic tweezers holder and placed into a covered plastic
carrier. The post-thickness or sheet resistance was then collected
on the post-processing test coupon surface by the 4-point probe,
CDE Resmap 273 for metallic film (Co, W, and W alloy) or by
Elipsometry for dielectric film (TiOx, SiN, SiC, and ILD) using a
Woollam M-2000X.
Formulation Examples FE-1-FE-7
Table 1 includes formulations FE-1 to FE-7 (which included a
sulfur-containing additive) prepared by General Procedure 1.
TABLE-US-00001 TABLE 1 Sulfur- Metal- Hydroxyl- First Second
containing containing Organic Ex. amine organic solvent organic
solvent additive additive Water acid FE-1 9.00% Hex DEGBE
3-amino-5- (NH.sub.4).sub.2TiF.sub.6 16% MSA glycol 10%
mercapto-1H- 0.008% 0.173% 64.75% 1,2,4-triazole 0.07% FE-2 9.00%
Hex DEGBE .beta.- (NH.sub.4).sub.2TiF.sub.6 16% MSA glycol 10%
mercaptoethanol 0.008% 0.154% 64.75% 0.047% FE-3 9.00% Hex DEGBE
3-amino-5- (NH.sub.4).sub.2TiF.sub.6 16% MSA glycol 10%
methylthio-1H- 0.008% 0.186% 64.75% 1,2,4-triazole 0.078% FE-4
9.00% Hex DEGBE 1-phenyl-1H- (NH.sub.4).sub.2TiF.sub.6 16% MSA
glycol 10% tetrazole-5-thiol 0.008% 0.137% 64.75% 0.107% FE-5 9.00%
Hex DEGBE 4-methyl-4H- (NH.sub.4).sub.2TiF.sub.6 16% MSA glycol 10%
1,2,4-triazole-3- 0.008% 0.189% 64.75% thiol 0.07% FE-6 9.00% Hex
DEGBE 2-pyridinethiol (NH.sub.4).sub.2TiF.sub.6 16% MSA glycol 10%
0.067% 0.008% 0.210% 64.75% FE-7 9.00% Hex DEGBE 3-mercapto-
(NH.sub.4).sub.2TiF.sub.6 16% MSA glycol 10% propionic acid 0.004%
0.168% 64.8% 0.04% DEGBE = diethylene glycol butyl ether; Hex
glycol = hexylene glycol; MSA = methanesulfonic acid
Examples 1-3
Compatibility of Cleaners with Exposed Metals or Dielectrics
Formulations FE-4, FE-6, and FE-7 were tested for cleaning ability
according to General Procedure 2 and for materials compatibility
according to General Procedure 3 at 65.degree. C. for 4 minutes.
The etch rates (ER) (Angstroms/minute) of Co, W, W alloy, TiOx,
SiN, SiC, and ILD by the cleaning compositions are shown in Table
2.
TABLE-US-00002 TABLE 2 Formulation Clean Example TiOx W Co ILD SiN
SiC W alloy (4 min.) FE-4 1.5 0 0.8 0 0 0 0.3 clean FE-6 1.6 0 0.8
0.1 0.6 0 0.1 clean FE-7 NA NA 1.4 NA NA NA 0.6 clean "NA" refers
to data not available.
The data in Table 2 show that formulations of this disclosure
(i.e., FE-4, FE-6, and FE-7) cleaned the post etch residue without
significantly etching the semiconductor materials (such as Co, W,
TiOx, SiN, SiC, TEOS, and ILD) typically found in semiconductor
devices.
Formulation Examples FE-8-FE-26 and CFE-1
Table 3 includes formulations FE-8 to FE-26 (which did not include
any sulfur-containing additive or any acid) prepared by General
Procedure 1.
TABLE-US-00003 TABLE 3 Hy- Hexylene Metal- Ph droxy- Glycol
containing Adjusting Ex. amine (Solvent) additive agent Water CFE-1
9% 78% none none Remainder FE-8 9% 78% 0.25% 1.22% Remainder
Ca(OH).sub.2 DBU FE-9 9% 78% 0.25% 0.22% Remainder
BaCl.sub.2.cndot.2H.sub.2O DBU FE-10 9% 78% 0.25% SrCl.sub.2 0.11%
Remainder DBU FE-11 9% 78% 0.25% LaCl.sub.3 2.58% Remainder DBU
FE-12 9% 78% 0.25% CeCl.sub.3 2.06% Remainder DBU FE-13 9% 78%
0.25% 0.92% Remainder (NH.sub.4).sub.2TiF.sub.6 DBU FE-14 9% 78%
0.0040% 0.07% Remainder (NH.sub.4).sub.2TiF.sub.6 DBU FE-15 9% 78%
0.0025% 0.04% Remainder (NH.sub.4).sub.2TiF.sub.6 DBU FE-16 9% 78%
0.0015% 0.03% Remainder (NH.sub.4).sub.2TiF.sub.6 DBU FE-17 9% 78%
0.0010% 0.02% Remainder (NH.sub.4).sub.2TiF.sub.6 DBU FE-18 9% 78%
0.25% none Remainder tungsten boride FE-19 9% 78% 0.10% none
Remainder tungsten boride FE-20 9% 78% 0.05% BaTiO.sub.3 none
Remainder FE-21 9% 78% 0.05%Ti (OEt).sub.4 none Remainder FE-22 9%
78% 0.05% none Remainder Ti(OCH(CH.sub.3).sub.2).sub.4 FE-23 9% 78%
0.0025% HfO.sub.2 0.03% Remainder DBU FE-24 9% 78% 0.0025%
V.sub.2O.sub.5 0.05% Remainder DBU FE-25 9% 78% 0.0025%
Nb.sub.2O.sub.5 0.03% Remainder DBU FE-26 9% 78% 0.0025% TaF.sub.3
0.06% Remainder DBU
Examples 4-22 and Comparative Example 1
Compatibility of Cleaners with Exposed Metals
Formulations FE-8 to FE-26, and CFE-1 were tested for materials
compatibility according to General Procedure 3 at 65.degree. C. for
4 minutes. The etch rates (ER) (Angstroms/minute) of W alloy, TiOx,
Co and W by the cleaning formulations are shown in Table 4.
TABLE-US-00004 TABLE 4 Ex. W Alloy TiOx Co W CFE-1 4.5 1.5 4.0 0.2
FE-8 2.0 0.1 0.8 0.0 FE-9 2.8 0.2 0.2 0.0 FE-10 2.6 0.3 8.6 0.0
FE-11 4.9 0.3 0.6 0.2 FE-12 5.5 4.4 0.4 0.2 FE-13 2.3 0.8 0.2 0.2
FE-14 0.8 0.5 0.8 0.1 FE-15 0.4 0.9 0.7 0.2 FE-16 0.4 0.9 0.7 0.1
FE-17 0.9 0.9 0.6 0.2 FE-18 1.9 0.1 0.6 0.0 FE-19 1.7 0.1 0.7 0.0
FE-20 1.4 0.2 0.6 0.0 FE-21 0.8 0.8 0.4 0.1 FE-22 0.2 0.9 0.4 0.0
FE-23 0.2 0.5 0.2 0.1 FE-24 0.6 1.7 0.1 0.6 FE-25 0.5 0.0 0.1 0.3
FE-26 1.0 0.7 0.3 0.2
The data in Table 4 show that cleaning formulations of this
disclosure (i.e., FE-8 to FE-26) significantly reduced corrosion or
etching of at least one of the metals (such as W, W alloy, Co, or
TiOx) typically found in semiconductor devices compared to a
cleaning formulation without any metal-containing additive.
Formulation Examples FE-27-FE-32
Table 5 includes formulations FE-27 to FE-32 (which included an
amino acid glycine) prepared by General Procedure 1.
TABLE-US-00005 TABLE 5 Hydroxyl- Hexylene Ex. amine glycol DEGBE
(NH.sub.4).sub.2TiF.sub.6 Glycine water FE-27 9% 65.77% 9.2%
0.0025% 0.03% 16% FE-28 9% 64.17% 10.8% 0.0025% 0.03% 16% FE-29 9%
64.97% 10% 0.0023% 0.03% 16% FE-30 9% 64.97% 10% 0.0027% 0.03% 16%
FE-31 9% 64.97% 10% 0.0025% 0.0276% 16% FE-32 9% 64.97% 10% 0.0025%
0.0324% 16%
Examples 23-28
Compatibility of Cleaners with Exposed Metals
Formulations FE-27 to FE-32 were tested for materials compatibility
according to General Procedure 3 at 65.degree. C. for 4 minutes.
The etch rates (ER) (Angstroms/minute) of W alloy, Co, AlOx, and
TiOx by the cleaning formulations are shown in Table 6.
TABLE-US-00006 TABLE 6 Ex. W alloy Co AlOx TiOx FE-27 1.7 .+-. 0.8
1.2 .+-. 0.3 3.1 .+-. 0.1 3.1 .+-. 0.0 FE-28 2.4 .+-. 0.7 1.1 .+-.
0.2 2.7 .+-. 0.1 2.3 .+-. 0.1 FE-29 1.7 .+-. 0.6 1.4 .+-. 0.1 2.2
.+-. 0.1 2.5 .+-. 0.0 FE-30 1.0 .+-. 0.3 1.0 .+-. 0.1 2.8 .+-. 0.1
2.6 .+-. 0.0 FE-31 3.7 .+-. 0.5 1.2 .+-. 0.1 2.5 .+-. 0.1 2.6 .+-.
0.1 FE-32 3.0 .+-. 0.2 1.1 .+-. 0.1 2.6 .+-. 0.1 2.3 .+-. 0.1
The data in Table 6 show that certain cleaning formulations of this
disclosure (i.e., FE-27 to FE-32) exhibited relatively low
corrosion or etching of the metals (such as W alloy, Co, AlOx, or
TiOx) typically found in semiconductor devices, which this low
corrosion did not change significantly due to the variations of the
amount of the solvents, the metal containing additive (i.e.,
NH.sub.4TiF.sub.6), and the amino acid (i.e., glycine) in the
formulations.
Formulation Examples FE-33-FE-40
Table 7 includes formulations FE-33 to FE-40 (which included an
amino acid glycine) prepared by General Procedure 1.
TABLE-US-00007 TABLE 7 Hydroxyl- Hexylene Ex. amine glycol DEGBE
(NH.sub.4).sub.2TiF.sub.6 Glycine water FE-33 9% 62% 10% 0.0025%
0.03% 18.9820% FE-34 9% 63% 10% 0.0025% 0.03% 17.9820% FE-35 9% 64%
10% 0.0025% 0.03% 16.9820% FE-36 9% 65% 10% 0.0025% 0.03% 15.9820%
FE-37 9% 66% 10% 0.0025% 0.03% 14.9820% FE-38 9% 67% 10% 0.0025%
0.03% 13.9820% FE-39 9% 68% 10% 0.0025% 0.03% 12.9820% FE-40 9% 69%
10% 0.0025% 0.03% 11.9820%
Examples 29-36
Compatibility of Cleaners with Exposed Metals
Formulations FE-33 to FE-40 were tested for materials compatibility
according to General Procedure 3 at 65.degree. C. for 4 minutes.
The etch rates (ER) (Angstroms/minute) of W alloy, Co, AlOx, and
TiOx by the cleaning formulations are shown in Table 8.
TABLE-US-00008 TABLE 8 Ex. W alloy Co AlOx TiOx FE-33 6.7 .+-. 0.1
1.4 .+-. 0.3 2.8 .+-. 0.0 3.4 .+-. 0.2 FE-34 2.5 .+-. 0.4 0.9 .+-.
0.1 2.1 .+-. 0.0 2.5 .+-. 0.1 FE-35 3.2 .+-. 0.3 1.2 .+-. 0.2 2.2
.+-. 0.3 2.7 .+-. 0.2 FE-36 2.8 .+-. 0.2 1.0 .+-. 0.2 2.3 .+-. 0.3
2.4 .+-. 0.0 FE-37 3.3 .+-. 0.4 0.8 .+-. 0.01 2.83 .+-. 0.02 2.29
.+-. 0.03 FE-38 2.5 .+-. 0.1 0.73 .+-. 0.01 2.64 .+-. 0.03 2.23
.+-. 0.02 FE-39 2.73 .+-. 0.3 0.63 .+-. 0.01 2.16 .+-. 0.03 2.02
.+-. 0.03 FE-40 2.7 .+-. 0.1 0.63 .+-. 0.01 2.0 .+-. 0.1 1.94 .+-.
0.02
The data in Table 8 show that certain cleaning formulations of this
disclosure (i.e., FE-33 to FE-40) exhibited relatively low
corrosion or etching of the metals (such as W alloy, Co, AlOx, or
TiOx) typically found in semiconductor devices and this low
corrosion did not change significantly due to the variations of the
amount of the solvents and water in the formulations.
Formulation Examples FE-41-FE-52
Table 9 includes formulations FE-41 to FE-52 (which included a
conductivity enhancing agent except for FE-41) prepared by General
Procedure 1.
TABLE-US-00009 TABLE 9 2- Conductivity Hydroxyl- Hexylene Pyridine-
enhancing Ex. amine glycol DEGBE (NH.sub.4).sub.2TiF.sub.6 Glycine
thiol MSA agent w- ater FE-41 9% 64.967% 10% 0.0025% 0.03% 0 0 0
16.001% FE-42 8.44% 60.66% 9.37% 0.008% 0 0.063% 1.48% 1.1% TMAH
18.87% FE-43 7.793% 56.040% 8.659% 0.007% 0 0.058% 1.377% 1.013%
TMAH 25.053% FE-44 7.793% 56.098% 8.659% 0.007% 0 0 1.377% 1.013%
TMAH 25.053% FE-45 7.790% 47.573% 8.66% 0.007% 0 0 4.52% 6.4% TEAH
25.05% FE-46 7.793% 46.98% 8.66% 0.007% 0 0 4.24% 7.27% BzTAH
25.05% FE-47 7.793% 51.51% 8.659% 0.007% 0 0 1.1% 2.88% TBAH
25.051% FE-48 7.793% 54.51% 8.659% 0.007% 0 0 1.1% 2.88% 25.05%
TBAH + 3.08% TBACl FE-49 7.793% 54.51% 8.659% 0.007% 0 0 1.1% 2.88%
25.05% TBAH + 6.16% TBACl FE-50 7.793% 55.35% 8.659% 0.007% 0 0
0.06% 3.08% 25.05% TBACl FE-51 7.793% 52.26% 8.659% 0.007% 0 0
0.07% 6.16% 25.05% TBACl FE-52 7.793% 55.73% 8.659% 0.007% 0 0
0.16% 2.6% 25.05% BMIMS TMAH: Tetramethylammonium hydroxide; TEAH:
Tetraethylammonium hydroxide; TBAH: Tetrabutylammonium hydroxide;
TBACl: Tetrabutylammonium chloride; BzTAH: Benzyltrimethylammonium
hydroxide; BMIMS: 1-Butyl-3-methyl-imidazolium-methanesulfonate
The conductivity of formulations FE-41 to FE-52 were measured using
a conductivity meter. The results are summarized in Table 10
below.
TABLE-US-00010 TABLE 10 Ex. Conductivity (.mu.S/cm) FE-41 16 FE-42
767 FE-43 720 FE-44 755 FE-45 2331 FE-46 677 FE-47 610 FE-48 1030
FE-49 1407 FE-50 673 FE-51 1245 FE-52 709
As shown in Table 10, formulations FE-42 to FE-52 (which included a
conductivity enhancing agent) all exhibited significantly higher
conductivity than formulation FE-41 (which did not include a
conductivity enhancing agent). Without wishing to be bound by
theory, it is believed that increasing the conductivity of the
cleaning formulation can result in a decreased Co loss during the
cleaning process. Thus, it is believed that formulations FE-42 to
FE-52 would have reduced Co loss compared to formulation FE-41.
While the disclosure has been described in detail with reference to
certain embodiments thereof, it is understood that modifications
and variations are within the spirit and scope of that which is
described and claimed.
* * * * *